My daughter loved DHS when she was 2, 3, and 4. She really doesn't remember much from Animal Kingdom, though. I don't really think it is as good as any of the zoos around here from strictly a zoo perspective. Now, Animal Kingdom is more than a zoo, so you need to take the other things into consideration. However, when you factor out the zoo parts because, again, I don't think the zoo parts are as good as the zoos around here, and just factor in the other parts of the park, for our family, it is not nearly as good as the other 3 parks.
Our daughter loved Play n Dine, Disney Junior Live on Stage, Little Mermaid, Beauty and the Beast, Great Movie Ride, Star Tours, and Tower of Terror. She rode those last 2 when she was 3. She also enjoyed Honey I Shrunk the Kids playset, but that's gone so rather moot. She doesn't talk about anything at Animal Kingdom except for the safari every now and then.